Purpose: We investigate the underlying biological effects and mechanisms of rESWT on myogenic contracture and muscle atrophy in a rabbit model of extending knee joint contracture.Materials and Methods: In group control, the knee joint was not fixed. In group I-4w, the knee joint was only fixed for 4 weeks. In groups SR-1 w, SR-2 w, and SR-4 w, the knee joint was fixed for 4 weeks before the rabbits underwent 1, 2, and 4 weeks of self-recovery, respectively. In groups rESWT-1 w, rESWT 2 w, and rESWT-4 w, the knee joint was fixed for 4 weeks before the rabbits underwent 1, 2, and 4 weeks of rESWT, respectively. The myogenic contracture was measured, the cross-sectional area and key protein levels for NF-κB/HIF-1α signaling pathway and myogenic regulatory factors were evaluated.Results: During the recovery period, biological findings showed that the levels of myogenic contracture and muscle atrophy were milder in group rESWT by compared with group SR after 2 weeks. Molecular biological analysis showed that MyoD protein levels in the group rESWT was significantly higher than those in the group SR, and importantly, phospho-NF-κB p65 and HIF-1α protein levels in the group rESWT were significantly lower than those in the group SR at the same time point.Conclusions: This is the first study demonstrated that rESWT has the potential to reduce myogenic contracture and muscle atrophy after long-term immobilization in animal model. It is a possible mechanism that changing the low oxygen environment in skeletal muscle through rESWT may inhibit activation of NF-κB/HIF-1α signaling pathway.
